A common grid tee construction comprises a metal strip formed into an upper bulb, a vertically extending double web and oppositely extending lower flanges. It is important for good appearance when there is no cap bridging the flanges and concealing the web elements that the spacing between these elements be uniform along the length of the web. This can be accomplished by fastening the web elements together adjacent the flanges. U.S. Pat. No. 4,489,529 to Ollinger proposes several ways to join the elements of the double web. One such proposal in this patent is to form stitches by lancing the double web elements at locations spaced along the length of the tee. A problem associated with this teaching is that the effective thickness of the web at the stitch locations is doubled. The resulting thickness variation makes it difficult to accurately hold the tee for subsequent forming and/or assembly operations during manufacture. Still further, variable thickness can present difficulties for the installer where the stitch exists or otherwise interferes at a cross tee slot.
Locating the stitches so that they do not interfere with critical parts of the tee is difficult and/or expensive where they are formed in a high speed rolling operation.
It is known to lance or stitch the double web elements in a manner where the material surrounding the lanced hole is coined to reduce the size of the hole after the lance is made to positively interlock the web elements together.